Organometallic compound, organic light-emitting device including the organometallic compound, and diagnostic composition including the organometallic compound

ABSTRACT

An organometallic compound represented by Formula 1: 
     
       
         
         
             
             
         
       
         
         
           
             wherein, in Formula 1, groups and variables are the same as described in the specification.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No.10-2017-0051886, filed on Apr. 21, 2017, in the Korean IntellectualProperty Office, and all the benefits accruing therefrom under 35 U.S.C.§ 119, the disclosure of which is incorporated herein in its entirety byreference.

BACKGROUND 1. Field

One or more embodiments relate to an organometallic compound, an organiclight-emitting device including the organometallic compound, and adiagnostic composition including the organometallic compound.

2. Description of the Related Art

Organic light-emitting devices (OLEDs) are self-emission devices, whichhave superior characteristics in terms of a viewing angle, a responsetime, a brightness, a driving voltage, and a response speed, and whichproduce full-color images.

In an example, an organic light-emitting device includes an anode, acathode, and an organic layer disposed between the anode and thecathode, wherein the organic layer includes an emission layer. A holetransport region may be disposed between the anode and the emissionlayer, and an electron transport region may be disposed between theemission layer and the cathode. Holes provided from the anode may movetoward the emission layer through the hole transport region, andelectrons provided from the cathode may move toward the emission layerthrough the electron transport region. The holes and the electronsrecombine in the emission layer to produce excitons. These excitonstransit from an excited state to a ground state, thereby generatinglight.

Meanwhile, luminescent compounds may be used to monitor, sense, ordetect a variety of biological materials including cells and proteins.An example of the luminescent compounds includes a phosphorescentluminescent compound.

Various types of organic light emitting devices are known. However,there still remains a need in OLEDs having low driving voltage, highefficiency, high brightness, and long lifespan.

SUMMARY

Aspects of the present disclosure provide an organometallic compound, anorganic light-emitting device including the organometallic compound, anda diagnostic composition including the organometallic compound.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

An aspect of the present disclosure provides an organometallic compoundrepresented by Formula 1 below:

In Formula 1,

M may be beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca),titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn),gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium (Ru), rhodium(Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt), or gold(Au),

two bonds selected from a bond between A₁ and M, a bond between X₂ andM, a bond between X₃ and M, and a bond between X₄ and M may each be acovalent bond, and the others thereof may each be a coordinate bond,

A₁ may be a first atom linked to M, a non-cyclic moiety including thefirst atom linked to M, or ring CY₁ including X₁ linked to M andsubstituted with groups R₁ in the number of a1,

the first atom may be B, N, P, C, Si, O, or S,

X₁ to X₄ may each independently be N or C,

rings CY₁ to CY₄ may each independently be selected from a C₅-C₃₀carbocyclic group and a C₁-C₃₀ heterocyclic group,

a cyclometalated ring formed by A₁, CY₂, and M may be a 5-membered ring,

X₃₁ may be C(R₃₁) or N, and X₃₂ may be C(R₃₂) or N, wherein, when X₃₁ isC(R₃₁) and X₃₂ is C(R₃₂), R₃₁ and R₃₂ may not be linked to each other,

T₁ and T₂ may each independently be selected from a single bond, adouble bond, *—N(R₅)—*′, *—B(R₅)—*′, *—P(R₅)—*′, *—C(R₅)(R₆)—*′,*—Si(R₅)(R₆)—*′, *—Ge(R₅)(R₆)—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′,*—S(═O)—*′, *—S(═O)₂—*′, *—C(R₅)═*′, *═C(R₅)—*′, C(R₅)═C(R₆)—*′,*—C(═S)—*′, and *—C≡C—*′, and * and *′ each indicate a binding site to aneighboring atom,

R₅ and R₆ may optionally be linked via a single bond, a double bond, ora first linking group to form a substituted or unsubstituted C₅-C₃₀carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclicgroup,

R₁ to R₆, R₃₁, and R₃₂ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, asubstituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group,—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉),

a1 to a4 may each independently be an integer from 0 to 20,

two of a plurality of neighboring groups R₁ may optionally be linked toform a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group,

two of a plurality of neighboring groups R₂ may optionally be linked toform a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group,

two of a plurality of neighboring groups R₃ may optionally be linked toform a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group,

two of a plurality of neighboring groups R₄ may optionally be linked toform a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group,

two or more neighboring groups selected from R₁ to R₄ may optionally belinked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic groupor a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

at least one substituent of the substituted C₅-C₃₀ carbocyclic group,the substituted C₁-C₃₀ heterocyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group,the substituted C₁-C₆₀ heteroaryl group, the substituted monovalentnon-aromatic condensed polycyclic group, and the substituted monovalentnon-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,—CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group,a hydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₆),—B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,—CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkylgroup, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxygroup, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, aC₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₂₁)(Q₂₂), —Si(Q₂₃) (Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉);and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃) (Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉),and

Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may each independentlybe selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkyl group substituted with atleast one selected from deuterium, a C₁-C₆₀ alkyl group, and a C₆-C₆₀aryl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkylgroup, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with at least oneselected from deuterium, a C₁-C₆₀ alkyl group, and a C₆-C₆₀ aryl group,a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroarylgroup, a monovalent non-aromatic condensed polycyclic group, and amonovalent non-aromatic condensed heteropolycyclic group.

Another aspect of the present disclosure provides an organiclight-emitting device including:

a first electrode,

a second electrode, and

an organic layer disposed between the first electrode and the secondelectrode,

wherein the organic layer includes an emission layer and at least one ofthe organometallic compound.

The organometallic compounds may act as a dopant in the organic layer.

Another aspect of the present disclosure provides a diagnosticcomposition including at least one organometallic compound representedby Formula 1.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a schematic view of an organic light-emitting device accordingto an embodiment;

FIG. 2 is a graph of intensity (arbitrary units, a. u.) versuswavelength (nanometers, nm), showing an ultraviolet (UV) absorptionspectrum and a photoluminescence (PL) spectrum in solution, with respectto Compound 1;

FIG. 3 is a graph of intensity (arbitrary units, a. u.) versuswavelength (nanometers, nm), showing an electroluminescence (EL)spectrum of an organic light-emitting device manufactured according toExample 1; and

FIG. 4 is a graph of luminescent efficiency (candelas per ampere, cd/A)vs. luminance (candelas per square meter) of an organic light-emittingdevice manufactured according to Example 1.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the presentembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theembodiments are merely described below, by referring to the figures, toexplain aspects of the present description. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items. Expressions such as “at least one of,” whenpreceding a list of elements, modify the entire list of elements and donot modify the individual elements of the list.

It will be understood that when an element is referred to as being “on”another element, it can be directly in contact with the other element orintervening elements may be present therebetween. In contrast, when anelement is referred to as being “directly on” another element, there areno intervening elements present.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers, and/or sections, these elements, components, regions, layers,and/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer, orsection from another element, component, region, layer, or section.Thus, a first element, component, region, layer, or section discussedbelow could be termed a second element, component, region, layer, orsection without departing from the teachings of the present embodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise.

The term “or” means “and/or.” It will be further understood that theterms “comprises” and/or “comprising,” or “includes” and/or “including”when used in this specification, specify the presence of statedfeatures, regions, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, regions, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this general inventive conceptbelongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand the present disclosure, and will not be interpreted in an idealizedor overly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

In an embodiment, an organometallic compound is provided. Theorganometallic compound according to an embodiment is represented byFormula 1 below:

M in Formula 1 may be beryllium (Be), magnesium (Mg), aluminum (Al),calcium (Ca), titanium (Ti), manganese(Mn), cobalt (Co), copper (Cu),zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium (Ru),rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt),or gold (Au).

For example, M may be Pt or Pd.

In an embodiment, M may be Pt, but embodiments of the present disclosureare not limited thereto.

In Formula 1, two bonds selected from a bond between A₁ and M, a bondbetween X₂ and M, a bond between X₃ and M, and a bond between X₄ and Mmay each be a covalent bond, and the others thereof may each be acoordinate bond. Accordingly, the organometallic compound represented byFormula 1 may be electrically neutral.

In an embodiment, a bond between A₁ and M and a bond between X₄ and Mmay each be a coordinate bond, and a bond between X₂ and M and a bondbetween X₃ and M may each be a covalent bond, but embodiments of thepresent disclosure are not limited thereto.

A₁ in Formula 1 may be a first atom linked to M, a non-cyclic moietyincluding the first atom linked to M, or a ring CY₁ including X₁ linkedto M and substituted with groups R₁ in the number of a1.

The first atom may be B, N, P, C, Si, O, or S.

For example, the first atom may be N, P, C, Si, or O, but embodiments ofthe present disclosure are not limited thereto.

In an embodiment, the first atom may be O.

The non-cyclic moiety including the first atom linked to M may be*—C(R₁₁)—*′, *—Si(R₁₁)—*′, *—B(R₁₁)—*′, *—N(R₁₁)—*′, *—P(R₁₁)—*′,*—C(R₁₁)(R₁₂)—*′, *—Si(R₁₁)(R₁₂)—*′, *—C(R₁₁)—C(═O)—*′,*—Si(R₁₁)—C(═O)—*′, *—B(R₁₁)—C(═O)—*′, *—N(R₁₁)—C(═O)—*′,*—P(R₁₁)—C(═O)—*′, *—C(R₁₁)(R₁₂)—C(═O)—*′, or *—Si(R₁₁)(R₁₂)—C(═O)—*′(wherein R₁₁ and R₁₂ are the same as described in connection with R₁, *indicates a binding site to M in Formula 1, and *′ indicates a bindingsite to T₂ in Formula 1).

X₁, a1, R₁, and CY₁ are the same as described herein.

X₁ to X₄ may each independently be N or C.

For example, X₁ and X₄ may each be N, and X₂ and X₃ may each be C, butembodiments of the present disclosure are not limited thereto.

Rings CY₁ to CY₄ may each independently be selected from a C₅-C₃₀carbocyclic group and a C₁-C₃₀ heterocyclic group.

For example, rings CY₁ to CY₄ may each independently be selected from abenzene group, a naphthalene group, an anthracene group, a phenanthrenegroup, a triphenylene group, a pyrene group, a chrysene group, acyclopentadiene group, a 1,2,3,4-tetrahydronaphthalene group, a furangroup, a thiophene group, a silole group, an indene group, a fluorenegroup, an indole group, a carbazole group, a benzofuran group, adibenzofuran group, a benzothiophene group, a dibenzothiophene group, abenzosilole group, a dibenzosilole group, an azafluorene group, anazacarbazole group, an azadibenzofuran group, an azadibenzothiophenegroup, an azadibenzosilole group, a pyridine group, a pyrimidine group,a pyrazine group, a pyridazine group, a triazine group, a quinolinegroup, an isoquinoline group, a quinoxaline group, a quinazoline group,a phenanthroline group, a pyrrole group, a pyrazole group, an imidazolegroup, a triazole group, an oxazole group, an isoxazole group, athiazole group, an isothiazole group, an oxadiazole group, a thiadiazolegroup, a benzopyrazole group, a benzimidazole group, a benzoxazolegroup, a benzothiazole group, a benzooxadiazole group, abenzothiadiazole group, a 5,6,7,8-tetrahydroisoquinoline group, and a5,6,7,8-tetrahydroquinoline group.

In an embodiment, at least one of rings CY₂ and CY₄ may be a condensedring in which at least one 5-membered ring is condensed with at leastone 6-membered ring, wherein the 5-membered ring may be selected from acyclopentadiene group, a furan group, a thiophene group, a pyrrolegroup, a silole group, an oxazole group, an isoxazole group, anoxadiazole group, an isoxadiazole group, an oxatriazole group, anisoxatriazole group, a thiazole group, an isothiazole group, athiadiazole group, an isothiadiazole group, a thiatriazole group, anisothiatriazole group, a pyrazole group, an imidazole group, a triazolegroup, a tetrazole group, an azasilole group, a diazasilole group, and atriazasilole group, and the 6-membered ring may be selected from acyclohexane group, a cyclohexene group, a benzene group, a pyridinegroup, a pyrimidine group, a pyrazine group, and a pyridazine group.

In an embodiment, at least one of rings CY₂ and CY₄ may be a condensedring with at least two 6-membered rings, wherein the 6-membered ring maybe selected from a cyclohexane group, a cyclohexene group, a benzenegroup, a pyridine group, a pyrimidine group, a pyrazine group, and apyridazine group, but embodiments of the present disclosure are notlimited thereto.

In an embodiment, when ring CY₂ is the condensed ring with the at leastone 5-membered ring and the at least one 6-membered ring, the 5-memberedring in the condensed ring may be linked to A₁ in Formula 1.

In one or more embodiments, when ring CY₂ is the condensed ring with theat least one 5-membered ring and the at least one 6-membered ring, the5-membered ring in the condensed ring may be linked to T₁ in Formula 1.

In one or more embodiments, when ring CY₄ is the condensed ring with theat least one 5-membered ring and the at least one 6-membered ring, the5-membered ring in the condensed ring may be linked to T₂ in Formula 1.

In one or more embodiments, when ring CY₄ is the condensed ring with theat least one 5-membered ring and the at least one 6-membered ring, the6-membered ring in the condensed ring may be linked to T₂ in Formula 1.

A cyclometalated ring formed by A₁, CY₂, and M in Formula 1 may be a5-membered ring.

In Formula 1, X₃₁ may be C(R₃₁) or N, and X₃₂ may be C(R₃₂) or N.

For example, X₃₁ may be C(R₃₁), and X₃₂ may be C(R₃₂) or N, butembodiments of the present disclosure are not limited thereto.

In Formula 1, when X₃₁ is C(R₃₁) and X₃₂ is C(R₃₂), R₃₁ and R₃₂ may notbe linked to each other.

T₁ and T₂ in Formula 1 may each independently be selected from a singlebond, a double bond, *—N(R₅)—*′, *—B(R₅)—*′, *—P(R₅)—*′, *—C(R₅)(R₆)—*′,*—Si(R₅)(R₆)—*′, *—Ge(R₅)(R₆)—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′,*—S(═O)—*′, *—S(═O)₂—*′, *—C(R₅)═*′, *═C(R₅)—*′, *—C(R₅)═C(R₆)—*′,*—C(═S)—*′, and *—C≡C—*′. R₅ and R₆ are the same as described herein,and R₅ and R₆ may optionally be linked via a single bond, a double bond,or a first linking group to form a substituted or unsubstituted C₅-C₃₀carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclicgroup.

The first linking group may be selected from *—N(R₇)—*′, *—B(R₇)—*′,*—P(R₇)—*′, *—C(R₇)(R₈)—*′, *—Si(R₇)(R₈)—*′, *—Ge(R₇)(R₈)—*′, *—S—*′,*—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₇)═*′,*═C(R₇)—*′, *—C(R₇)═C(R₈)—*′, *—C(═S)—*′, and *—C≡C—*′, R₇ and R₈ arethe same as described in connection with R₅, and * and *′ each indicatea binding site to a neighboring atom.

In an embodiment, T₂ may be a single bond.

In one or more embodiments, T₁ may be selected from a single bond,*—N(R₅)—*′, *—C(R₅)(R₆)—*′, *—Si(R₅)(R₆)—*′, *—S—*′, *—O—*′, and*—C(═O)—*′, and T₂ may be a single bond, but embodiments of the presentdisclosure are not limited thereto.

At least one of R₅ and R₆ may optionally be linked to at least one ofCY₂ and CY₃ in Formula 1 via a single bond, a double bond, or a secondlinking group to form a substituted or unsubstituted C₅-C₃₀ carbocyclicgroup or a substituted or unsubstituted C₁-C₃₀ heterocyclic group. Thesecond linking group is the same as described in connection with thefirst linking group.

R₁ to R₆, R₃₁, and R₃₂ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, asubstituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group,—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₅)(Q₉).

For example, R₁ to R₆, R₃₁, and R₃₂ may each independently be selectedfrom:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,—SF₅, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂,—CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, anamino group, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkylgroup, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclooctyl group, an adamantanyl group, a norbornanyl group, anorbornenyl group, a cyclopentenyl group, a cyclohexenyl group, acycloheptenyl group, a phenyl group, a naphthyl group, a pyridinylgroup, and a pyrimidinyl group;

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclooctyl group, an adamantanyl group, a norbornanyl group, anorbornenyl group, a cyclopentenyl group, a cyclohexenyl group, acycloheptenyl group, a phenyl group, a naphthyl group, a fluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group,an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a dibenzosilolyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group;

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclooctyl group, an adamantanyl group, a norbornanyl group, anorbornenyl group, a cyclopentenyl group, a cyclohexenyl group, acycloheptenyl group, a phenyl group, a naphthyl group, a fluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group,an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a dibenzosilolyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,—CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group,an amidino group, a hydrazine group, a hydrazone group, a carboxylicacid group or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptylgroup, a cyclooctyl group, an adamantanyl group, a norbornanyl group, anorbornenyl group, a cyclopentenyl group, a cyclohexenyl group, acycloheptenyl group, a phenyl group, a naphthyl group, a fluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group,an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a dibenzosilolyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, animidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅); and

—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉), wherein

Q₁ to Q₉ and Q₃₃ to Q₃₅ may each independently be selected from:

—CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃,—CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and —CD₂CDH₂;

an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butylgroup, a sec-butyl group, a tert-butyl group, an n-pentyl group, anisopentyl group, a sec-pentyl group, a tert-pentyl group, a phenylgroup, and a naphthyl group; and

an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butylgroup, a sec-butyl group, a tert-butyl group, an n-pentyl group, anisopentyl group, a sec-pentyl group, a tert-pentyl group, a phenylgroup, and a naphthyl group, each substituted with at least one selectedfrom deuterium, a C₁-C₁₀ alkyl group, and a phenyl group.

In an embodiment, R₁ to R₆, R₃₁, and R₃₂ may each independently beselected from hydrogen, deuterium, —F, a cyano group, a nitro group,—SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, groups representedby Formulae 9-1 to 9-19, groups represented by Formulae 10-1 to 10-161,—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉) (wherein Q₁to Q₉ are the same as described herein), but embodiments of the presentdisclosure are not limited thereto:

In Formulae 9-1 to 9-19 and 10-1 to 10-161, “Ph” indicates a phenylgroup, “TMS” indicates a trimethylsilyl group, and * indicates a bindingsite to a neighboring atom.

In an embodiment, in Formula 1, X₃₁ may be C(R₃₁), X₃₂ may be C(R₃₂),and at least one of R₃₁ and R₃₂ may not be hydrogen.

In one or more embodiments, in Formula 1, X₃₁ may be C(R₃₁), X₃₂ may beC(R₃₂), and R₃₁ and R₃₂ may be identical to each other.

In one or more embodiments, in Formula 1, X₃₁ may be C(R₃₁), X₃₂ may beC(R₃₂), and at least one of R₃₁ and R₃₂ (for example, i) R₃₁ or ii) R₃₁and R₃₂ may be selected from a substituted or unsubstituted C₁-C₆₀ alkylgroup, a substituted or unsubstituted C₂-C₆₀ alkenyl group, asubstituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅),—B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉) (for example, at least one of R₃₁ and R₃₂may be selected from —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂,groups represented by Formulae 9-1 to 9-19, groups represented byFormulae 10-1 to 10-161, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and—P(═O)(Q₈)(Q₉)).

In one or more embodiments, in Formula 1, X₃₁ may be C(R₃₁), X₃₂ may beC(R₃₂), and at least one of R₃₁ and R₃₂ (for example, i) R₃₁ or ii) R₃₁and R₃₂) may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group(for example, at least one of R₃₁ and R₃₂ may be selected from groupsrepresented by Formulae 10-1 to 10-161).

In one or more embodiments, in Formula 1, X₃₁ may be C(R₃₁), and R₃₁ maybe selected from a substituted or unsubstituted C₁-C₆₀ alkyl group, asubstituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted orunsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstitutedC₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₆), —B(Q₆)(Q₇), and—P(═O)(Q₈)(Q₉) (for example, R₃₁ may be selected from —CH₃, —CD₃, —CD₂H,—CDH₂, —CF₃, —CF₂H, —CFH₂, groups represented by Formulae 9-1 to 9-19,groups represented by Formulae 10-1 to 10-161, —N(Q₁)(Q₂),—Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉)).

a1, a2, a3, and a4 respectively indicate the number of groups R₁, thenumber of groups R₂, the number of groups R₃, and the number of groupsR₄, and may each independently be an integer from 0 to 20 (for example,an integer from 0 to 4). When a1 is two or more, two or more groups R₁may be identical to or different from each other, when a2 is two ormore, two or more groups R₂ may be identical to or different from eachother, when a3 is two or more, two or more groups R₃ may be identical toor different from each other, and when a4 is two or more, two or moregroups R₄ may be identical to or different from each other.

In an embodiment, A₁ in Formula 1 may be selected from moietiesrepresented by Formulae CY1-1 to CY1-44 and A1-1 to A1-4:

In Formulae CY1-1 to CY1-44 and A1-1 to A1-4,

X₁ and R₁ are the same as described herein,

X₁₁ may be O, S, N(R₁₁), C(R₁₁)(R₁₂), or Si(R₁₁)(R₁₂),

R₁₁ to R₁₈ are the same as described in connection with R₁,

a16 may be an integer from 0 to 6,

a15 may be an integer from 0 to 5,

a14 may be an integer from 0 to 4,

a13 may be an integer from 0 to 3,

a12 may be an integer from 0 to 2,

* indicates a binding site to M in Formula 1, and

*′ indicates a binding site to ring CY₂ in Formula 1.

In one or more embodiments, a moiety represented by

in Formula 1 may be represented by one of Formulae CY2-1 to CY2-45:

In Formulae CY2-1 to CY2-45,

X₂ and R₂ are the same as described herein,

X₂₁ may be O, S, N(R₂₁), C(R₂₁)(R₂₂), or Si(R₂₁)(R₂₂),

R₂₁ to R₂₈ are the same as described in connection with R₂,

a26 may be an integer from 0 to 6,

a25 may be an integer from 0 to 5,

a24 may be an integer from 0 to 4,

a23 may be an integer from 0 to 3,

a22 may be an integer from 0 to 2,

* indicates a binding site to M in Formula 1,

*′ indicates a binding site to A₁ in Formula 1, and

*″ indicates a binding site to T₁ in Formula 1.

In one or more embodiments, a moiety represented by

in Formula 1 may be represented by one of Formulae CY3-1 to CY3-10:

In Formulae CY3-1 to CY3-10,

X₃, R₃, X₃₁, and X₃₂ are the same as described herein,

R₃₁ to R₃₈ are the same as described in connection with R₃,

a34 may be an integer from 0 to 4,

a33 may be an integer from 0 to 3,

a32 may be an integer from 0 to 2,

* indicates a binding site to M in Formula 1,

*″ indicates a binding site to T₁ in Formula 1, and

*′ indicates a binding site to T₂ in Formula 1.

In one or more embodiments, a moiety represented by

in Formula 1 may be represented by one of Formulae CY4-1 to CY4-44:

In Formulae CY4-1 to CY4-44,

X₄ and R₄ are the same as described herein,

X₄₁ may be O, S, N(R₄₁), C(R₄₁)(R₄₂), or Si(R₄₁)(R₄₂),

R₄₁ to R₄₈ are the same as described in connection with R₄,

a46 may be an integer from 0 to 6,

a45 may be an integer from 0 to 5,

a44 may be an integer from 0 to 4,

a43 may be an integer from 0 to 3,

a42 may be an integer from 0 to 2,

* indicates a binding site to M in Formula 1, and

*′ indicates a binding site to T₂ in Formula 1.

In one or more embodiments, in Formula 1,

A₁ may be selected from moieties represented by Formulae CY1(1) toCY1(19), and/or

the moiety represented by

may be represented by one of Formulae CY2(1) to CY2(13), and/or

the moiety represented by

may be represented by one of Formulae CY3(1) to CY3(18), and/or

the moiety represented by

may be represented by one of Formulae CY4(1) to CY4(11):

In Formulae CY1 (1) to CY1 (19), CY2(1) to CY2(13), CY3(1) to CY3(18),and CY4(1) to CY4(11),

X₁ to X₄, R₁ to R₄, R₃₁, and R₃₂ are the same as described herein,

X₁₁ may be O, S, N(R₁₁), C(R₁₁)(R₁₂), or Si(R₁₁)(R₁₂),

X₂₁ may be O, S, N(R₂₁), C(R₂₁)(R₂₂), or Si(R₂₁)(R₂₂),

X₄₁ may be O, S, N(R₄₁), C(R₄₁)(R₄₂), or Si(R₄₁)(R₄₂),

R_(1a) to R_(1d), R₁₁, and R₁₂ are the same as described in connectionwith R₁,

R_(2a), R_(2b), R₂₁, and R₂₂ are the same as described in connectionwith R₂,

R_(4a) to R_(4d), R₄₁, and R₄₂ are the same as described in connectionwith R₄,

* in Formulae CY1(1) to CY1(19), CY2(1) to CY2(13), CY3(1) to CY3(18),and CY4(1) to CY4(11) indicates a binding site to M in Formula 1,

*′ in Formulae CY1(1) to CY1(19) indicates a binding site to ring CY2 inFormula

*′ in Formulae CY2(1) to CY2(13) indicates a binding site to A₁ inFormula 1,

*″ in Formulae CY2(1) to CY2(13) indicates a binding site to T₁ inFormula 1,

*″ in Formulae CY3(1) to CY3(18) indicates a binding site to T₁ inFormula 1,

*′ in Formulae CY3(1) to CY3(18) indicates a binding site to T₂ inFormula 1, and

*′ in Formulae CY4(1) to CY4(11) indicates a binding site to T₂ inFormula 1.

In one or more embodiments, the organometallic compound represented byFormula 1 may be represented by Formula 1-1:

In Formula 1-1,

M, A₁, X₂ to X₄, CY₂ to CY₄, X₃₁, X₃₂, T₂, R₂ to R₄, and a2 to a4 arethe same as described herein,

X₉ and X₁₀ may each independently be C or N,

CY₉ and CY₁₀ may each independently be selected from a C₅-C₃₀carbocyclic group and a C₁-C₆₀ heterocyclic group (for example, CY₉ andCY₁₀ are the same as described in connection with CY₁),

R₉ and R₁₀ are the same as described in connection with R₁,

a9 and a10 are the same as described in connection with a1,

T₃ may be C, Si, or Ge,

T₄ may be selected from a single bond, a double bond, *—N(R₇)—*′,*—B(R₇)—*′, *—P(R₇)—*′, *—C(R₇)(R₉)—*′, *—Si(R₇)(R₉)—*′,*—Ge(R₇)(R₉)—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′,*—S(═O)₂—*′, *—C(R₇)═*′, *═C(R₇)—*′, *—C(R₇)═C(R₉)—*′, *—C(═S)—*′, and*—C≡C—*′, and * and *′ each indicate a binding site to a neighboringatom,

R₇ and R₈ are the same as described in connection with R₅, and

* and *′ each indicate a binding site to a neighboring atom.

In Formula 1, i) two of a plurality of neighboring groups R₁ mayoptionally be linked to form a substituted or unsubstituted C₅-C₃₀carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclicgroup, ii) two of a plurality of neighboring groups R₂ may optionally belinked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic groupor a substituted or unsubstituted C₁-C₃₀ heterocyclic group, iii) two ofa plurality of neighboring groups R₃ may optionally be linked to form asubstituted or unsubstituted C₅-C₃₀ carbocyclic group or a substitutedor unsubstituted C₁-C₃₀ heterocyclic group, iv) two of a plurality ofneighboring groups R₄ may optionally be linked to form a substituted orunsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstitutedC₁-C₃₀ heterocyclic group, and v) two or more neighboring groupsselected from R₁ to R₄ may optionally be linked to form a substituted orunsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstitutedC₁-C₃₀ heterocyclic group.

For example, i) a substituted or unsubstituted C₅-C₃₀ carbocyclic groupor a substituted or unsubstituted C₁-C₃₀ heterocyclic group, formed bylinking two of a plurality of neighboring groups R₁, ii) a substitutedor unsubstituted C₅-C₃₀ carbocyclic group or a substituted orunsubstituted C₁-C₃₀ heterocyclic group, formed by linking two of aplurality of neighboring groups R₂, iii) a substituted or unsubstitutedC₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀heterocyclic group, formed by linking two of a plurality of neighboringgroups R₃, iv) a substituted or unsubstituted C₅-C₃₀ carbocyclic groupor a substituted or unsubstituted C₁-C₃₀ heterocyclic group, formed bylinking two of a plurality of neighboring groups R₄, and v) asubstituted or unsubstituted C₅-C₃₀ carbocyclic group or a substitutedor unsubstituted C₁-C₃₀ heterocyclic group, formed by two or moreneighboring groups selected from R₁ to R₄ in Formula 1, may eachindependently be selected from:

a cyclopentadiene group, a cyclohexane group, a cycloheptane group, anadamantane group, a bicycloheptane group, a bicyclo-octane group, abenzene group, a pyridine group, a pyrimidine group, a pyrazine group, apyridazine group, a naphthalene group, an anthracene group, a tetracenegroup, a phenanthrene group, a dihydronaphthalene group, a phenalenegroup, a benzothiophene group, a benzofuran group, an indene group, anindole group, a benzosilole group, an azabenzothiophene group, anazabenzofuran group, an azaindene group, an azaindole group, and anazabenzosilole group; and

a cyclopentadiene group, a cyclohexane group, a cycloheptane group, anadamantane group, a bicycloheptane group, a bicyclo-octane group, abenzene group, a pyridine group, a pyrimidine group, a pyrazine group, apyridazine group, a naphthalene group, an anthracene group, a tetracenegroup, a phenanthrene group, a dihydronaphthalene group, a phenalenegroup, a benzothiophene group, a benzofuran group, an indene group, anindole group, a benzosilole group, an azabenzothiophene group, anazabenzofuran group, an azaindene group, an azaindole group, and anazabenzosilole group, each substituted with at least one R₁₀,

but embodiments of the present disclosure are not limited thereto.

R₁₀ is the same as described in connection with R₁.

“An azabenzothiophene group, an azabenzofuran group, an azaindene group,an azaindole group, an azabenzosilole group, an azadibenzothiophenegroup, an azadibenzofuran group, an azafluorene group, an azacarbazolegroup, and an azadibenzosilole group” used herein mean hetero-rings thatrespectively have the same backbones as “a benzothiophene group, abenzofuran group, an indene group, an indole group, an benzosilolegroup, a dibenzothiophene group, a dibenzofuran group, a fluorene group,a carbazole group, and a dibenzosilole group”, provided that at leastone of carbons forming rings thereof is substituted with nitrogen.

For example, the organometallic compound may be one of Compounds 1 to105, but embodiments of the present disclosure are not limited thereto:

A cyclometalated ring formed by A₁, CY₂, and M in Formula 1 is a5-membered ring. Accordingly, the molecular stability of theorganometallic compound may be improved, and the efficiency (forexample, maximum luminescence quantum efficiency or the like) and/orlifespan of an electronic device, for example, an organic light-emittingdevice, which includes the organometallic compound, may be improved.

Also, in Formula 1, when X₃₁ is C(R₃₁) and X₃₂ is C(R₃₂), R₃₁ and R₃₂are not linked to each other. Accordingly, aggregation betweenorganometallic compound molecules may be prevented, and the efficiency(for example, maximum luminescence quantum efficiency or the like) andlifespan of an electronic device, for example, an organic light-emittingdevice, which includes an organometallic compound, may be improved.

For example, a highest occupied molecular orbital (HOMO) energy level, alowest unoccupied molecular orbital (LUMO) energy level, an energy bandgap (E_(g)) energy level, a singlet (S₁) energy level, and a triplet(T₁) energy level of some Compounds were evaluated by using a densityfunctional theory (DFT) method of a Gaussian program (B3LYP,structurally optimized at a level of 6-31G(d,p)). Evaluation results areshown in Table 1.

TABLE 1 Com- E_(g) energy S₁ energy T₁ pound HOMO LUMO level levelenergy level No. (eV) (eV) (eV) (eV) (eV) 1 −4.204 −1.42 2.781 2.2481.978 2 −4.152 −1.635 2.517 2.04 1.846 3 −4.202 −1.434 2.769 2.233 1.9644 −4.181 −1.45 2.731 2.197 1.934 16 −4.228 −1.418 2.81 2.271 2 17 −4.24−1.436 2.804 2.265 1.996 18 −4.339 −1.534 2.805 2.266 1.998 19 −4.176−1.634 2.542 2.062 1.87 22 −4.102 −1.613 2.489 2.018 1.834 23 −4.11−1.641 2.469 2.003 1.812 25 −4.204 −1.6 2.604 2.111 1.91 44 −4.23 −1.6672.563 2.066 1.875 45 −4.205 −1.535 2.67 2.157 1.944 71 −4.496 −1.6272.869 2.316 2.046 72 −4.49 −1.625 2.865 2.312 2.044 73 −4.449 −1.8932.555 2.038 1.851 74 −4.443 −1.561 2.882 2.32 2.054 A −4.633 −1.6233.010 2.449 2.179 B −4.390 −1.594 2.796 2.312 2.277

From Table 1, it is confirmed that the organometallic compoundrepresented by Formula 1 has such electrical characteristics that aresuitable for use in an electronic device, for example, for use as adopant for an organic light-emitting device.

Synthesis methods of the organometallic compound represented by Formula1 may be recognizable by those of ordinary skill in the art by referringto Synthesis Examples provided below.

The organometallic compound represented by Formula 1 is suitable for usein an organic layer of an organic light-emitting device, for example,for use as a dopant in an emission layer of the organic layer. Thus,another aspect provides an organic light-emitting device that includes:

a first electrode;

a second electrode; and

an organic layer that is disposed between the first electrode and thesecond electrode, wherein the organic layer includes an emission layerand at least one of the organometallic compound represented by Formula1.

The organic light-emitting device may have, due to the inclusion of anorganic layer including the organometallic compound represented byFormula 1, a low driving voltage, high efficiency, high power, highquantum efficiency, a long lifespan, a low roll-off ratio, and excellentcolor purity.

The organometallic compound of Formula 1 may be used between a pair ofelectrodes of an organic light-emitting device. For example, theorganometallic compound represented by Formula 1 may be included in theemission layer. In this regard, the organometallic compound may act as adopant, and the emission layer may further include a host (that is, anamount of the organometallic compound represented by Formula 1 issmaller than an amount of the host).

The expression “(an organic layer) includes at least one oforganometallic compounds” used herein may include an embodiment in which“(an organic layer) includes identical organometallic compoundsrepresented by Formula 1” and an embodiment in which “(an organic layer)includes two or more different organometallic compounds represented byFormula 1.”

For example, the organic layer may include, as the organometalliccompound, only Compound 1. In this regard, Compound 1 may be included inan emission layer of the organic light-emitting device. In one or moreembodiments, the organic layer may include, as the organometalliccompound, Compound 1 and Compound 2. In this embodiment, Compound 1 andCompound 2 may be included in an identical layer (for example, Compound1 and Compound 2 all may be included in an emission layer).

The first electrode may be an anode, which is a hole injectionelectrode, and the second electrode may be a cathode, which is anelectron injection electrode; or the first electrode may be a cathode,which is an electron injection electrode, and the second electrode maybe an anode, which is a hole injection electrode.

In an embodiment, in the organic light-emitting device, the firstelectrode is an anode, and the second electrode is a cathode, and theorganic layer further includes a hole transport region disposed betweenthe first electrode and the emission layer and an electron transportregion disposed between the emission layer and the second electrode,wherein the hole transport region includes a hole injection layer, ahole transport layer, an electron blocking layer, or any combinationthereof, and wherein the electron transport region includes a holeblocking layer, an electron transport layer, an electron injectionlayer, or any combination thereof.

The term “organic layer” as used herein refers to a single layer and/ora plurality of layers between the first electrode and the secondelectrode of the organic light-emitting device. The “organic layer” mayinclude, in addition to an organic compound, an organometallic complexincluding metal.

FIG. 1 is a schematic view of an organic light-emitting device 10according to an embodiment. Hereinafter, the structure of an organiclight-emitting device according to an embodiment and a method ofmanufacturing an organic light-emitting device according to anembodiment will be described in connection with FIG. 1. The organiclight-emitting device 10 includes a first electrode 11, an organic layer15, and a second electrode 19, which are sequentially stacked.

A substrate may be additionally disposed under the first electrode 11 orabove the second electrode 19. For use as the substrate, any substratethat is used in general organic light-emitting devices may be used, andthe substrate may be a glass substrate or a transparent plasticsubstrate, each having excellent mechanical strength, thermal stability,transparency, surface smoothness, ease of handling, and waterresistance.

The first electrode 11 may be formed by depositing or sputtering amaterial for forming the first electrode 11 on the substrate. The firstelectrode 11 may be an anode. The material for forming the firstelectrode 11 may be selected from materials with a high work function tofacilitate hole injection. The first electrode 11 may be a reflectiveelectrode, a semi-transmissive electrode, or a transmissive electrode.The material for forming the first electrode may be, for example, indiumtin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO₂), and zincoxide (ZnO). In one or more embodiments, magnesium (Mg), aluminum (Al),aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), ormagnesium-silver (Mg—Ag) may be used as the material for forming thefirst electrode.

The first electrode 11 may have a single-layered structure or amulti-layered structure including two or more layers. For example, thefirst electrode 11 may have a three-layered structure of ITO/Ag/ITO, butthe structure of the first electrode 110 is not limited thereto.

The organic layer 15 is disposed on the first electrode 11.

The organic layer 15 may include a hole transport region, an emissionlayer, and an electron transport region.

The hole transport region may be disposed between the first electrode 11and the emission layer.

The hole transport region may include a hole injection layer, a holetransport layer, an electron blocking layer, a buffer layer, or anycombination thereof.

The hole transport region may include only either a hole injection layeror a hole transport layer. In one or more embodiments, the holetransport region may have a hole injection layer/hole transport layerstructure or a hole injection layer/hole transport layer/electronblocking layer structure, which are sequentially stacked in this statedorder from the first electrode 11.

A hole injection layer may be formed on the first electrode 11 by usingone or more suitable methods selected from vacuum deposition, spincoating, casting, or Langmuir-Blodgett (LB) deposition.

When a hole injection layer is formed by vacuum deposition, thedeposition conditions may vary according to a compound that is used toform the hole injection layer, and the structure and thermalcharacteristics of the hole injection layer. For example, the depositionconditions may include a deposition temperature of about 100° C. toabout 500° C., a vacuum pressure of about 10⁻⁸ torr to about 10⁻³ torr,and a deposition rate of about 0.01 Å/sec to about 100 Å/sec. However,the deposition conditions are not limited thereto.

When the hole injection layer is formed using spin coating, coatingconditions may vary according to the material used to form the holeinjection layer, and the structure and thermal properties of the holeinjection layer. For example, a coating speed may be from about 2,000revolutions per minute (rpm) to about 5,000 rpm, and a temperature atwhich a heat treatment is performed to remove a solvent after coatingmay be from about 80° C. to about 200° C. However, the coatingconditions are not limited thereto.

Conditions for forming a hole transport layer and an electron blockinglayer may be understood by referring to conditions for forming the holeinjection layer.

The hole transport region may include at least one selected fromm-MTDATA, TDATA, 2-TNATA, NPB, 8-NPB, TPD, spiro-TPD, spiro-NPB,methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine(TCTA), polyaniline/dodecylbenzene sulfonic acid (PANI/DBSA),poly(3,4-ethylenedioxythiophene)/poly(4-styrene sulfonate) (PEDOT/PSS),polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), a compound represented by Formula 201 below, anda compound represented by Formula 202 below:

Ar₁₀₁ and Ar₁₀₂ in Formula 201 may each independently be selected from:

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anacenaphthylene group, a fluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenylene group, a pyrenylene group, a chrysenylenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, and a pentacenylene group; and

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anacenaphthylene group, a fluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenylene group, a pyrenylene group, a chrysenylenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, and a pentacenylene group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group.

xa and xb in Formula 201 may each independently be an integer from 0 to5, or may each independently be 0, 1, or 2. For example, xa may be 1,and xb may be 0, but embodiments of the present disclosure are notlimited thereto.

R₁₀₁ to R₁₀₈, R₁₁₁ to R₁₁₉, and R₁₂₁ to R₁₂₄ in Formulae 201 and 202 mayeach independently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₁₀ alkyl group (for example, a methyl group, an ethyl group, apropyl group, a butyl group, pentyl group, a hexyl group, and so on),and a C₁-C₁₀ alkoxy group (for example, a methoxy group, an ethoxygroup, a propoxy group, a butoxy group, a pentoxy group, and so on);

a C₁-C₁₀ alkyl group and a C₁-C₁₀ alkoxy group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, and a phosphoric acidgroup or a salt thereof;

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenylgroup, and a pyrenyl group; and

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenylgroup, and a pyrenyl group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₁₀ alkyl group, and a C₁-C₁₀ alkoxy group,

but embodiments of the present disclosure are not limited thereto.

R₁₀₉ in Formula 201 may be selected from:

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinylgroup; and

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinylgroup, each substituted with at least one selected from deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkylgroup, a C₁-C₆₀ alkoxy group, a phenyl group, a naphthyl group, ananthracenyl group, and a pyridinyl group.

According to an embodiment, the compound represented by Formula 201 maybe represented by Formula 201A, but embodiments of the presentdisclosure are not limited thereto:

R₁₀₁, R₁₁₁, R₁₁₂, and R₁₀₉ in Formula 201A may be understood byreferring to the description provided herein.

For example, the compound represented by Formula 201, and the compoundrepresented by Formula 202 may include compounds HT1 to HT20 illustratedbelow, but are not limited thereto.

A thickness of the hole transport region may be in a range of about 100Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When thehole transport region includes at least one of a hole injection layerand a hole transport layer, the thickness of the hole injection layermay be in a range of about 100 Å to about 10,000 Å, and for example,about 100 Å to about 1,000 Å, and the thickness of the hole transportlayer may be in a range of about 50 Å to about 2,000 Å, and for example,about 100 Å to about 1,500 Å. While not wishing to be bound by theory,it is understood that when the thicknesses of the hole transport region,the hole injection layer, and the hole transport layer are within theseranges, satisfactory hole transporting characteristics may be obtainedwithout a substantial increase in driving voltage.

The hole transport region may further include, in addition to thesematerials, a charge-generation material for the improvement ofconductive properties. The charge-generation material may behomogeneously or non-homogeneously dispersed in the hole transportregion.

The charge-generation material may be, for example, a p-dopant. Thep-dopant may be one selected from a quinone derivative, a metal oxide,and a cyano group-containing compound, but embodiments of the presentdisclosure are not limited thereto. Non-limiting examples of thep-dopant are a quinone derivative, such as tetracyanoquinonedimethane(TCNQ) or 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane(F4-TCNQ); a metal oxide, such as a tungsten oxide or a molybdeniumoxide; and a cyano group-containing compound, such as Compound HT-D1below, but are not limited thereto.

The hole transport region may include a buffer layer.

Also, the buffer layer may compensate for an optical resonance distanceaccording to a wavelength of light emitted from the emission layer, andthus, efficiency of a formed organic light-emitting device may beimproved.

Then, an emission layer may be formed on the hole transport region byvacuum deposition, spin coating, casting, LB deposition, or the like.When the emission layer is formed by vacuum deposition or spin coating,the deposition or coating conditions may be similar to those applied informing the hole injection layer although the deposition or coatingconditions may vary according to a compound that is used to form theemission layer.

Meanwhile, when the hole transport region includes an electron blockinglayer, a material for the electron blocking layer may be selected frommaterials for the hole transport region described above and materialsfor a host to be explained later. However, the material for the electronblocking layer is not limited thereto. For example, when the holetransport region includes an electron blocking layer, a material for theelectron blocking layer may be mCP, which will be explained later.

The emission layer may include a host and a dopant, and the dopant mayinclude the organometallic compound represented by Formula 1.

The host may include at least one selected from TPBi, TBADN, ADN (alsoreferred to as “DNA”), CBP, CDBP, TCP, mCP, Compound H50, and CompoundH51:

In one or more embodiments, the host may further include a compoundrepresented by Formula 301 below.

Ar₁₁₁ and Ar₁₁₂ in Formula 301 may each independently be selected from:

a phenylene group, a naphthylene group, a phenanthrenylene group, and apyrenylene group; and

a phenylene group, a naphthylene group, a phenanthrenylene group, and apyrenylene group, each substituted with at least one selected from aphenyl group, a naphthyl group, and an anthracenyl group.

Ar₁₁₃ to Ar₁₁₆ in Formula 301 may each independently be selected from:

a C₁-C₁₀ alkyl group, a phenyl group, a naphthyl group, a phenanthrenylgroup, and a pyrenyl group; and

a phenyl group, a naphthyl group, a phenanthrenyl group, and a pyrenylgroup, each substituted with at least one selected from a phenyl group,a naphthyl group, and an anthracenyl group.

g, h, i, and j in Formula 301 may each independently be an integer from0 to 4, for example, 0, 1, or 2.

Ar₁₁₃ to Ar₁₁₆ in Formula 301 may each independently be selected from:

a C₁-C₁₀ alkyl group substituted with at least one selected from aphenyl group, a naphthyl group, and an anthracenyl group;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group,a phenanthrenyl group, and a fluorenyl group;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group,a phenanthrenyl group, and a fluorenyl group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a naphthylgroup, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, anda fluorenyl group; and

but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, the host may include a compound representedby Formula 302 below:

Ar₁₂₂ to Ar₁₂₅ in Formula 302 are the same as described in connectionwith Ar₁₁₃ in Formula 301.

Ar₁₂₆ and Ar₁₂₇ in Formula 302 may each independently be a C₁-C₁₀ alkylgroup (for example, a methyl group, an ethyl group, or a propyl group).

k and l in Formula 302 may each independently be an integer from 0 to 4.For example, k and l may be 0, 1, or 2.

When the organic light-emitting device is a full-color organiclight-emitting device, the emission layer may be patterned into a redemission layer, a green emission layer, and a blue emission layer. Inone or more embodiments, due to a stacked structure including a redemission layer, a green emission layer, and/or a blue emission layer,the emission layer may emit white light.

When the emission layer includes a host and a dopant, an amount of thedopant may be in a range of about 0.01 parts by weight to about 15 partsby weight based on 100 parts by weight of the host, but embodiments ofthe present disclosure are not limited thereto.

A thickness of the emission layer may be in a range of about 100 Å toabout 1,000 Å, for example, about 200 Å to about 600 Å. While notwishing to be bound by theory, it is understood that when the thicknessof the emission layer is within this range, excellent light-emissioncharacteristics may be obtained without a substantial increase indriving voltage.

Then, an electron transport region may be disposed on the emissionlayer.

The electron transport region may include a hole blocking layer, anelectron transport layer, an electron injection layer, or anycombination thereof.

For example, the electron transport region may have a hole blockinglayer/electron transport layer/electron injection layer structure or anelectron transport layer/electron injection layer structure, but thestructure of the electron transport region is not limited thereto. Theelectron transport layer may have a single-layered structure or amulti-layered structure including two or more different materials.

Conditions for forming the hole blocking layer, the electron transportlayer, and the electron injection layer which constitute the electrontransport region may be understood by referring to the conditions forforming the hole injection layer.

When the electron transport region includes a hole blocking layer, thehole blocking layer may include, for example, at least one of BCP,Bphen, and BAlq but embodiments of the present disclosure are notlimited thereto.

A thickness of the hole blocking layer may be in a range of about 20 Åto about 1,000 Å, for example, about 30 Å to about 300 Å. While notwishing to be bound by theory, it is understood that when the thicknessof the hole blocking layer is within these ranges, the hole blockinglayer may have improved hole blocking ability without a substantialincrease in driving voltage.

The electron transport layer may further include at least one selectedfrom BCP, Bphen, Alq₃, BAlq, TAZ, and NTAZ:

In one or more embodiments, the electron transport layer may include atleast one of ET1 to ET25, but are not limited thereto:

A thickness of the electron transport layer may be in a range of about100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. Whilenot wishing to be bound by theory, it is understood that when thethickness of the electron transport layer is within the range describedabove, the electron transport layer may have satisfactory electrontransport characteristics without a substantial increase in drivingvoltage.

Also, the electron transport layer may further include, in addition tothe materials described above, a metal-containing material.

The metal-containing material may include a Li complex. The Li complexmay include, for example, Compound ET-D1 (lithium 8-hydroxyquinolate,LiQ) or ET-D2:

The electron transport region may include an electron injection layerthat promotes flow of electrons from the second electrode 19 thereinto.

The electron injection layer may include at least one selected from LiF,NaCl, CsF, Li₂O, and BaO.

A thickness of the electron injection layer may be in a range of about 1Å to about 100 Å, for example, about 3 Å to about 90 Å. While notwishing to be bound by theory, it is understood that when the thicknessof the electron injection layer is within the range described above, theelectron injection layer may have satisfactory electron injectioncharacteristics without a substantial increase in driving voltage.

The second electrode 19 is disposed on the organic layer 15. The secondelectrode 19 may be a cathode. A material for forming the secondelectrode 19 may be selected from metal, an alloy, an electricallyconductive compound, and a combination thereof, which have a relativelylow work function. For example, lithium (Li), magnesium (Mg), aluminum(Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In),or magnesium-silver (Mg—Ag) may be used as a material for forming thesecond electrode 19. In one or more embodiments, to manufacture atop-emission type light-emitting device, a transmissive electrode formedusing ITO or IZO may be used as the second electrode 19.

Hereinbefore, the organic light-emitting device has been described withreference to FIG. 1, but embodiments of the present disclosure are notlimited thereto.

Another aspect of the present disclosure provides a diagnosticcomposition including at least one organometallic compound representedby Formula 1.

The organometallic compound represented by Formula 1 provides highluminescent efficiency. Accordingly, a diagnostic composition includingthe organometallic compound may have high diagnostic efficiency.

The diagnostic composition may be used in various applications includinga diagnosis kit, a diagnosis reagent, a biosensor, and a biomarker.

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear orbranched saturated aliphatic hydrocarbon monovalent group having 1 to 60carbon atoms, and non-limiting examples thereof include a methyl group,an ethyl group, a propyl group, an iso-butyl group, a sec-butyl group, atert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group.The term “C₁-C₆₀ alkylene group” as used herein refers to a divalentgroup having the same structure as the C₁-C₆₀ alkyl group.

The term “C₁-C₆₀ alkoxy group” as used herein refers to a monovalentgroup represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group),and non-limiting examples thereof include a methoxy group, an ethoxygroup, and an iso-propyloxy group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a hydrocarbongroup formed by including at least one carbon-carbon double bond in themiddle or at the terminus of the C₂-C₆₀ alkyl group, and examplesthereof include an ethenyl group, a propenyl group, and a butenyl group.The term “C₂-C₆₀ alkenylene group” as used herein refers to a divalentgroup having the same structure as the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a hydrocarbongroup formed by including at least one carbon-carbon triple bond in themiddle or at the terminus of the C₂-C₆₀ alkyl group, and examplesthereof include an ethynyl group, and a propynyl group. The term “C₂-C₆₀alkynylene group” as used herein refers to a divalent group having thesame structure as the C₂-C₆₀ alkynyl group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalentsaturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, andnon-limiting examples thereof include a cyclopropyl group, a cyclobutylgroup, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.The term “C₃-C₁₀ cycloalkylene group” as used herein refers to adivalent group having the same structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein refers to amonovalent saturated monocyclic group having at least one heteroatomselected from N, O, P, Si and S as a ring-forming atom and 1 to 10carbon atoms, and non-limiting examples thereof include atetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term“C₁-C₁₀ heterocycloalkylene group” as used herein refers to a divalentgroup having the same structure as the C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group” as used herein refers to amonovalent monocyclic group that has 3 to 10 carbon atoms and at leastone carbon-carbon double bond in the ring thereof and no aromaticity,and non-limiting examples thereof include a cyclopentenyl group, acyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀cycloalkenylene group” as used herein refers to a divalent group havingthe same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein refers to amonovalent monocyclic group that has at least one heteroatom selectedfrom N, O, P, Si, and S as a ring-forming atom, 1 to 10 carbon atoms,and at least one carbon-carbon double bond in its ring. Examples of theC₁-C₁₀ heterocycloalkenyl group are a 2,3-dihydrofuranyl group, and a2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylenegroup” as used herein refers to a divalent group having the samestructure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein refers to a monovalent grouphaving a carbocyclic aromatic system having 6 to 60 carbon atoms, andthe term “C₆-C₆₀ arylene group” as used herein refers to a divalentgroup having a carbocyclic aromatic system having 6 to 60 carbon atoms.Non-limiting examples of the C₆-C₆₀ aryl group include a phenyl group, anaphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenylgroup, and a chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀arylene group each include two or more rings, the rings may be fused toeach other.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalentgroup having an aromatic system that has at least one heteroatomselected from N, O, P, Si, and S as a ring-forming atom, and 1 to 60carbon atoms. The term “C₁-C₆₀ heteroarylene group” as used hereinrefers to a divalent group having an aromatic system that has at leastone heteroatom selected from N, O, P, Si and S as a ring-forming atom,and 1 to 60 carbon atoms. Non-limiting examples of the C₁-C₆₀ heteroarylgroup include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group,a pyridazinyl group, a triazinyl group, a quinolinyl group, and anisoquinolinyl group. When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀heteroarylene group each include two or more rings, the rings may befused to each other.

The term “C₆-C₆₀ aryloxy group” used herein indicates —OA₁₀₂ (whereinA₁₀₂ is the C₆-C₆₀ aryl group), and a C₆-C₆₀ arylthio group used hereinindicates —SA₁₀₃ (wherein A103 is the C₆-C₆₀ aryl group).

The term “monovalent non-aromatic condensed polycyclic group” as usedherein refers to a monovalent group (for example, having 8 to 60 carbonatoms) having two or more rings condensed to each other, only carbonatoms as ring-forming atoms, and no aromaticity in its entire molecularstructure. Examples of the monovalent non-aromatic condensed polycyclicgroup include a fluorenyl group. The term “divalent non-aromaticcondensed polycyclic group,” used herein, refers to a divalent grouphaving the same structure as the monovalent non-aromatic condensedpolycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” asused herein refers to a monovalent group (for example, having 2 to 60carbon atoms) having two or more rings condensed to each other, aheteroatom selected from N, O, P, Si, and S, other than carbon atoms, asa ring-forming atom, and no aromaticity in its entire molecularstructure. Non-limiting examples of the monovalent non-aromaticcondensed heteropolycyclic group include a carbazolyl group. The term“divalent non-aromatic condensed heteropolycyclic group” as used hereinrefers to a divalent group having the same structure as the monovalentnon-aromatic condensed heteropolycyclic group.

The term “C₆-C₃₀ carbocyclic group” as used herein refers to a saturatedor unsaturated cyclic group having, as a ring-forming atom, 5 to 30carbon atoms only. The C₆-C₃₀ carbocyclic group may be a monocyclicgroup or a polycyclic group.

The term “C₁-C₃₀ heterocyclic group” as used herein refers to asaturated or unsaturated cyclic group having, as a ring-forming atom, atleast one heteroatom selected from N, O, Si, P, and S other than 1 to 30carbon atoms. The C₁-C₃₀ heterocyclic group may be a monocyclic group ora polycyclic group.

At least one substituent of the substituted C₆-C₃₀ carbocyclic group,the substituted C₂-C₃₀ heterocyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group,the substituted C₁-C₆₀ heteroaryl group, the substituted monovalentnon-aromatic condensed polycyclic group, and the substituted monovalentnon-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,—CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group,an amidino group, a hydrazine group, a hydrazone group, a carboxylicacid group or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, aC₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₆),—B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,—CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group,a nitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, aC₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅),—B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉); and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₆), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉),wherein

Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may each independentlybe selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl groupsubstituted with at least one selected from a C₁-C₆₀ alkyl group and aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, and a monovalent non-aromatic condensed heteropolycyclic group.

When a group containing a specified number of carbon atoms issubstituted with any of the groups listed in the preceding paragraph,the number of carbon atoms in the resulting “substituted” group isdefined as the sum of the carbon atoms contained in the original(unsubstituted) group and the carbon atoms (if any) contained in thesubstituent. For example, when the term “substituted C₁-C₃₀ alkyl”refers to a C₁-C₃₀ alkyl group substituted with C₆-C₃₀ aryl group, thetotal number of carbon atoms in the resulting aryl substituted alkylgroup is C₇-C₆₀.

Hereinafter, a compound and an organic light-emitting device accordingto embodiments are described in detail with reference to SynthesisExamples and Examples. However, the organic light-emitting device is notlimited thereto. The wording “B was used instead of A” used indescribing Synthesis Examples means that an amount of A used wasidentical to an amount of B used, in terms of a molar equivalent.

EXAMPLES Synthesis Example 1: Synthesis of Compound 1

Synthesis of Intermediate 1-4

35.4 grams (g) (150 millimoles, mmol) of 1,3-dibromobenzene, 14.1 g (150mmol) of 2-aminopyridine, 4.25 g (7.5 mmol) ofbis(dibenzylideneacetone)palladium(0) (Pd(dba)₂), 6.0 g (15 mmol) oftri-tert-butylphosphine (P(t-Bu)₃), and 21.6 g (225 mmol) of sodiumtert-butoxide (NaOtBu) were added to a flask, 500 milliliters (mL) oftoluene was added thereto, and the flask was purged with nitrogen. Theresultant mixture was refluxed for 24 hours, cooled to room temperature,and extracted by using dichloromethane/water (MC/H₂O). The organic layerwas dried by using magnesium sulfate (MgSO₄) and then concentrated. Thecrude product was purified by column chromatography (hexane/ethylacetate=3/1) to obtain Intermediate 1-4 (yield=65%).

Synthesis of Intermediate 1-3

14.8 g (60 mmol) of Intermediate 1-4, 16.0 g (90 mmol) ofdiphenylacetylene, 16.9 g (126 mmol) of CuCl₂, and 0.78 g (3.0 mmol) ofbis(acetonitrile)dichloropalladium (Pd(CH₃CN)₂Cl₂) were added to aflask, 300 mL of DMF was added thereto, and the flask was purged withnitrogen. Then, the resultant mixture was allowed to react at atemperature of 105° C. for 12 hours. Then, the mixture was cooled toroom temperature and extracted by using dichloromethane/water (MC/H₂O).The organic layer was dried by using magnesium sulfate (MgSO₄) andconcentrated. The crude product was purified by column chromatography(hexane/ethyl acetate=20/1) to obtain Intermediate 1-3 (yield=90%).

Synthesis of Intermediate 1-2

23.4 g (100 mmol) of 2-(3-bromophenyl)pyridine, 9.3 g (100 mmol) ofaniline, 2.87 g (5.0 mmol) of bis(dibenzylideneacetone)palladium(0)(Pd(dba)₂), 2.0 g (10 mmol) of tri-tert-butylphosphine (P(t-Bu)₃), and14.4 g (150 mmol) of sodium tert-butoxide (NaOtBu) were added to aflask, 200 mL of toluene was added thereto, and the flask was purgedwith nitrogen. The resultant mixture was refluxed for 24 hours, cooledto room temperature, and extracted by using dichloromethane/water(MC/H₂O). The organic layer was dried by using magnesium sulfate (MgSO₄)and concentrated. The crude product was purified by columnchromatography (hexane/ethyl acetate=3/1) to obtain Intermediate 1-2(yield=75%).

Synthesis of Intermediate 1-1

Intermediate 1-1 (yield=82%) was synthesized in the same manner in whichIntermediate 1-2 was synthesized, except that Intermediate 1-2 was usedinstead of aniline.

Synthesis of Compound 1

3.38 g (3.5 mmol) of Intermediate 1-1, 0.93 g (3.5 mmol) of platinumchloride, and 100 mL of cyanobenzene were added to a 500-mL round bottomflask, and the mixture was refluxed for 24 hours. After the reaction wascompleted, the mixture was cooled to room temperature, and the solventwas distilled off under reduced pressure. The crude product was purifiedby column chromatography by using methylene chloride and normal hexaneas a developing solvent to obtain 1.4 g (yield=52%) of Compound 1.

LCMS: m/z calcd for C₄₂H₂₈N₄Pt=783.20; Found [M+H]⁺=784.29.

Synthesis Example 2: Synthesis of Compound 16

Synthesis of Intermediate 16-1

Intermediate 16-1 (yield=78%) was synthesized in the same manner inwhich Intermediate 1-1 was synthesized in Synthesis Example 1, exceptthat Intermediate 16-2 was used instead of Intermediate 1-2.

Synthesis of Compound 16

Compound 16 (yield=45%) was synthesized in the same manner in whichCompound 1 was synthesized in Synthesis Example 1, except thatIntermediate 16-1 was used instead of Intermediate 1-1.

LCMS: m/z calcd for C₄₈H₃₂N₄Pt=859.23; Found [M+H]⁺=860.27.

Synthesis Example 3: Synthesis of Compound 19

Synthesis of Intermediate 19-3

Intermediate 19-3 (yield=88%) was synthesized in the same manner inwhich Intermediate 1-3 was synthesized in Synthesis Example 1, exceptthat Intermediate 19-4 was used instead of Intermediate 1-4.

Synthesis of Intermediate 19-1

Intermediate 19-1 (yield=75%) was synthesized in the same manner inwhich Intermediate 1-1 was synthesized in Synthesis Example 1, exceptthat Intermediate 19-2 and Intermediate 19-3 were respectively usedinstead of Intermediate 1-2 and Intermediate 1-3.

Synthesis of Compound 19

Compound 19 (yield=47%) was synthesized in the same manner in whichCompound 1 was synthesized in Synthesis Example 1, except thatIntermediate 19-1 was used instead of Intermediate 1-1.

LCMS: m/z calcd for C₆₀H₄₀N₄Pt=1011.29; Found [M+H]⁺=1012.34.

Synthesis Example 4: Synthesis of Compound 45

Synthesis of Intermediate 45-1

Intermediate 45-1 (yield=80%) was synthesized in the same manner inwhich Intermediate 1-1 was synthesized in Synthesis Example 1, exceptthat Intermediate 45-2 was used instead of Intermediate 1-2.

Synthesis of Compound 45

Compound 45 (yield=43%) was synthesized in the same manner in whichCompound 1 was synthesized in Synthesis Example 1, except thatIntermediate 45-1 was used instead of Intermediate 1-1.

LCMS: m/z calcd for C₅₅H₃₈N₄Pt=949.27; Found [M+H]⁺=948.27.

Synthesis Example 5: Synthesis of Compound 49

Synthesis of Intermediate 49-1

Compound 49-1 (yield=81%) was synthesized in the same manner in whichIntermediate 1-1 was synthesized in Synthesis Example 1, except thatIntermediate 49-2 was used instead of Intermediate 1-2.

Synthesis of Compound 49

Compound 49 (yield=47%) was synthesized in the same manner in whichCompound 1 was synthesized in Synthesis Example 1, except thatIntermediate 49-1 was used instead of Intermediate 1-1.

LCMS: m/z calcd for C₆₁H₄₂N₄Pt=1025.31; Found [M+H]⁺=1026.34.

Synthesis Example 6: Synthesis of Compound 72

Synthesis of Intermediate 72-2

19.7 g (80 mmol) of 2-bromo-9H-carbazole, 31.3 g (85 mmol) of2-(tributylstannyl)pyridine, and 4.62 g (4 mmol) oftetrakis(triphenylphosphine)palladium(0) (Pd(PPh₃)₄) were added to aflask, 160 mL of DMF was added thereto, and the flask was purged withnitrogen. The resultant mixture was refluxed for 24 hours, cooled toroom temperature, and extracted by using dichloromethane/water (MC/H₂O).The organic layer was dried by using magnesium sulfate (MgSO₄) andconcentrated. The crude product was purified by column chromatography(hexane/methylene chloride=3/1) to obtain Intermediate 72-2 (yield=59%).

Synthesis of Intermediate 72-1

Intermediate 72-1 (yield=75%) was synthesized in the same manner inwhich Intermediate 1-1 was synthesized in Synthesis Example 1, exceptthat Intermediate 72-2 was used instead of Intermediate 1-2.

Synthesis of Compound 72

Compound 72 (yield=42%) was synthesized in the same manner in whichCompound 1 was synthesized in Synthesis Example 1, except thatIntermediate 72-1 was used instead of Intermediate 1-1.

LCMS: m/z calcd for C₄₂H₂₆N₄Pt=781.18; Found [M+H]⁺=782.29.

Comparative Synthesis Example A: Synthesis of Compound A

Synthesis of Intermediate A-1

Intermediate A-1 (yield=74%) was synthesized in the same manner in whichIntermediate 72-1 was synthesized in Synthesis Example 6, except thatIntermediate A-3 was used instead of Intermediate 1-3.

Synthesis of Compound A

Compound A (yield=38%) was synthesized in the same manner in whichCompound 1 was synthesized in Synthesis Example 1, except thatIntermediate A-1 was used instead of Intermediate 1-1.

LCMS: m/z calcd for C₃₄H₂₀N₄Pt=679.13; Found [M+H]⁺=680.17.

Comparative Synthesis Example B: Synthesis of Compound B

Synthesis of Intermediate B-4

14.4 g (50 mmol) of Intermediate B-5, 10.1 g (50 mmol) of1-bromo-2-nitrobenzene, 17.3 g (125 mmol) of K₂CO₃, and 2.9 g (2.5 mmol)of tetrakis(triphenylphosphine)palladium(0) (Pd(PPh₃)₄) were added to aflask, and 150 mL of THF/H₂O (3/1) was added thereto. The resultantmixture was refluxed for 24 hours, cooled to room temperature, andextracted by using ethyl acetate/water (EA/H₂O). The organic layer wasdried by using magnesium sulfate (MgSO₄) and concentrated. The crudeproduct was purified by column chromatography (hexane/methylenechloride=2/1) to obtain Intermediate B-4 (yield=67%).

Synthesis of Intermediate B-3

19 g (52 mmol) of Intermediate B-4 and 54 g (206 mmol) oftriphenylphosphine were added to a flask, and 170 mL of dichlorobenzenewas added thereto. The resultant mixture was allowed to react at atemperature of 175° C. for 24 hours. The resultant mixture was cooled toroom temperature, and the crude product was purified by columnchromatography (hexane/methylene chloride=1/1) to obtain a solid. Thesolid was washed by using methanol to obtain Intermediate B-3(yield=70%).

Synthesis of Intermediate B-1

Intermediate B-1 (yield=72%) was synthesized in the same manner in whichIntermediate 1-1 was synthesized in Synthesis Example 1, except thatIntermediate B-2 and Intermediate B-3 were respectively used instead ofIntermediate 1-2 and Intermediate 1-3.

Synthesis of Compound B

Compound B(yield=25%) was synthesized in the same manner in whichCompound 1 was synthesized in Synthesis Example 1, except thatIntermediate B-1 was used instead of Intermediate 1-1.

LCMS: m/z calcd for C₃₅H₂₂N₆Pt=721.16; Found [M+H]⁺=722.21.

Evaluation Example 1: Evaluation of UV-Vis Absorption Spectrum andPhotoluminescence (PL) Spectrum

Luminescent characteristics of each Compound were evaluated byevaluating a UV-Vis absorption spectrum and a PL spectrum of Compound 1.Compound 1 was diluted at a concentration of 1×10⁻⁵ M in MeTHF, and aUV-Vis absorption spectrum was measured at room temperature by using aShimadzu UV-350 spectrometer. Compound 1 was diluted at a concentrationof 10 mM in MeTHF, and a PL spectrum thereof was measured at roomtemperature by using an ISC PC1 spectrofluorometer equipped with a xenonlamp. Results thereof are shown in Table 2. Referring to FIG. 2, it isconfirmed that Compound 1 has a UV-Vis absorption spectrum and a PLspectrum suitable for use in an electronic device, for example, anorganic light-emitting device.

Evaluation Example 2: Measurement of Decay Time

A quartz substrate washed with chloroform and distilled water wasprepared, and films 1 to 6, A, and B, each having a thickness of 50 nm,were prepared by vacuum-depositing (co-depositing) certain materialsshown in Table 2 below at a degree of vacuum of 10⁻⁷ torr.

TABLE 2 Film name Compound used to manufacture film Film 1 CBP:Compound1 (weight ratio of 9:1) Film 2 CBP:Compound 16 (weight ratio of 9:1)Film 3 CBP:Compound 19 (weight ratio of 9:1) Film 4 CBP:Compound 45(weight ratio of 9:1) Film 5 CBP:Compound 49 (weight ratio of 9:1) Film6 CBP:Compound 72 (weight ratio of 9:1) Film A CBP:Compound A (weightratio of 9:1) Film B CBP:Compound B (weight ratio of 9:1)

Then, PL spectra of the films 1 to 6, A, and B prepared as describedabove were evaluated at room temperature by using a time-resolvedphotoluminescence (TRPL) measurement system FluoTime 300 (manufacturedby PicoQuant) and a pumping source PLS340 (excitation wavelength=340nanometers (nm), spectral width=20 nm) (manufactured by PicoQuant),wavelengths of main peaks of the PL spectra were determined, and thenumber of photons emitted from each film at the main peak by a photonpulse (pulse width=500 picoseconds, ps) applied to each film by PLS340was measured over time using Time-Correlated Single Photon Counting(TCSPC). By repeating the above processes, a sufficiently fittable TRPLcurve was obtained. Then, a decay time value T_(decay)(Ex) of each ofthe films 1 to 5, A, and B was obtained by fitting two or moreexponential decay functions to a result obtained from the TRPL curve.Results thereof are shown in Table 3. A function represented by Equation1 was used for the fitting, and a greatest value among values T_(decay)obtained from the exponential decay functions used for the fitting wastaken as T_(decay)(Ex). At this time, the same measurement was performedonce more for the same measurement time as that for calculating the TRPLcurve in a dark state (a state in which the pumping signal input to acertain film was blocked) to obtain a baseline or background signalcurve. The baseline or background curve was used as a baseline forfitting.

$\begin{matrix}{{f(t)} = {\sum\limits_{i = 1}^{n}{A_{i}\mspace{11mu}{\exp\left( {{- t}\text{/}T_{{decay},i}} \right)}}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

TABLE 3 Decay time Film name (micrometers, μm) Film 1 7.08 Film 2 7.01Film 3 5.98 Film 4 6.72 Film 5 6.14 Film 6 8.78 Film A 9.01 Film B 9.58

Referring to Table 3, it is confirmed that Compounds 1, 16, 19, 45, 49,and 72 each have a shorter decay time, as compared with Compounds A andB.

Example 1

As an anode, a glass substrate, on which ITO/Ag/ITO were respectivelydeposited to thicknesses of 70 Å/1,000 Å/70 Å (Å=Angstrom), was cut to asize of 50 mm×50 mm×0.5 mm (mm=millimeter), sonicated with iso-propylalcohol and pure water each for 5 minutes, and then cleaned by exposureto ultraviolet rays and ozone for 30 minutes. Then, the glass substratewas provided to a vacuum deposition apparatus.

2-TNATA was deposited on the anode to form a hole injection layer havinga thickness of 600 Å, and 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl(NPB) was deposited on the hole injection layer to form a hole transportlayer having a thickness of 1,350 Å.

CBP (host) and Compound 1 (dopant) were co-deposited on the holetransport layer at a weight ratio of 98:2 to form an emission layerhaving a thickness of 400 Å, and BCP was deposited on the emission layerto form a hole blocking layer having a thickness of 50 Å. Then, Alq₃ wasdeposited on the hole blocking layer to form an electron transport layerhaving a thickness of 350 Å, LiF was deposited on the electron transportlayer to form an electron injection layer having a thickness of 10 Å,and MgAg was deposited on the electron injection layer at a weight ratioof 90:10 to form a cathode having a thickness of 120 Å, therebycompleting the manufacture of an organic light-emitting device (emittingred color light) having a structure of ITO/Ag/ITO/2-TNATA (600 Å)/NPB(1,350 Å)/CBP+Compound 1 (2 wt %) (400 Å)/BCP (50 Å)/Alq₃ (350 Å)/LiF(10Å)/MgAg (120 Å).

Examples 2 to 6 and Comparative Examples A and B

Organic light-emitting devices were manufactured in the same manner asin Example 1, except that Compounds shown in Table 4 were each usedinstead of Compound 1 as a dopant in forming an emission layer.

Evaluation Example 3: Evaluation of Characteristics of OrganicLight-Emitting Devices

The driving voltage, maximum luminescence quantum efficiency, maximumemission wavelength, and color purity of the organic light-emittingdevices manufactured according to Examples 1 to 6 and ComparativeExamples A and B were evaluated, and results thereof are shown in Table4. This evaluation was performed by using a current-voltage meter(Keithley 2400) and a luminance meter (Minolta Cs-1,000A). FIGS. 3 and 4respectively show an EL spectrum and a graph of luminance vs.luminescent efficiency of the organic light-emitting device manufacturedaccording to Example 1.

TABLE 4 Maximum luminescence Maximum Driving quantum emission voltageefficiency wavelength Dopant (V) (%) (nm) CIE_x Example 1 Compound 4.9717.2 613 0.635 1 Example 2 Compound 4.91 18.5 611 0.633 16 Example 3Compound 4.85 20.5 625 0.657 19 Example 4 Compound 4.75 18.3 615 0.65245 Example 5 Compound 4.64 19.1 613 0.635 49 Example 6 Compound 4.2716.7 596 0.598 72 Comparative Compound 4.67 15.8 554 0.346 Example A AComparative Compound 5.06 16.5 532 0.257 Example B B

Referring to Table 4, it is confirmed that the organic light-emittingdevices of Examples 1 to 6 have improved maximum luminescence quantumefficiency and can emit red light having excellent color purity, ascompared to the organic light-emitting devices of Comparative Examples Aand B.

As described above, the organometallic compounds according to theembodiments of the present disclosure have excellent electricalcharacteristics and thermal stability, and accordingly, organiclight-emitting devices including such organometallic compounds may haveexcellent driving voltage, efficiency, power, color purity, and lifespancharacteristics. Also, due to excellent phosphorescent luminescencecharacteristics, such organometallic compounds may provide a diagnosticcomposition having high diagnostic efficiency.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While one or more embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the present disclosure as definedby the following claims.

What is claimed is:
 1. An organometallic compound represented by Formula1:

wherein, in Formula 1, M is beryllium (Be), magnesium (Mg), aluminum(Al), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper(Cu), zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium(Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum(Pt), or gold (Au), two bonds selected from a bond between A₁ and M, abond between X₂ and M, a bond between X₃ and M, and a bond between X₄and M are each a covalent bond, and the others thereof are each acoordinate bond, A₁ is a first atom linked to M, a non-cyclic moietycomprising the first atom linked to M, or ring CY₁ comprising X₁ linkedto M and substituted with groups R₁ in the number of a1, the first atomis B, N, P, C, Si, O, or S, X₁ and X₂ are each independently N or C, X₃is C and X₄ is N, rings CY₁ to CY₄ are each independently selected froma C₅-C₃₀ carbocyclic group and a C₁-C₃₀ heterocyclic group, acyclometalated ring formed by A₁, CY₂, and M is a 5-membered ring, X₃₁is C(R₃₁) or N, and X₃₂ is C(R₃₂) or N, wherein, when X₃₁ is C(R₃₁) andX₃₂ is C(R₃₂), R₃₁ and R₃₂ are not linked to each other, T₁ and T₂ mayeach independently be selected from a single bond, a double bond,*—N(R₅)—*′, *—B(R₅)—*′, *—P(R₅)—*′, *—C(R₅)(R₆)—*′, *—Si(R₅)(R₆)—*′,*—Ge(R₅)(R₆)—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′,*—S(═O)₂—*′, *—C(R₅)═*′, *═C(R₅)—*′, C(R₅)═C(R₆)—*′, *—C(═S)—*′, and*—C≡C—*′, and * and *′ each indicate a binding site to a neighboringatom, R₅ and R₆ may optionally be linked via a single bond, a doublebond, or a first linking group to form a substituted or unsubstitutedC₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀heterocyclic group, R₁ to R₆, R₃₁, and R₃₂ may each independently beselected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, asubstituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted orunsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstitutedC₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and—P(═O)(Q₈)(Q₉), a₁ to a₄ are each independently an integer from 0 to 20,two of a plurality of neighboring groups R₁ are optionally linked toform a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group, two of aplurality of neighboring groups R₂ are optionally linked to form asubstituted or unsubstituted C₅-C₃₀ carbocyclic group or a substitutedor unsubstituted C₁-C₃₀ heterocyclic group, two of a plurality ofneighboring groups R₃ are optionally linked to form a substituted orunsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstitutedC₁-C₃₀ heterocyclic group, two of a plurality of neighboring groups R₄are optionally linked to form a substituted or unsubstituted C₅-C₃₀carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclicgroup, two or more neighboring groups selected from R₁ to R₄ areoptionally linked to form a substituted or unsubstituted C₅-C₃₀carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclicgroup, at least one substituent of the substituted C₅-C₃₀ carbocyclicgroup, the substituted C₁-C₃₀ heterocyclic group, the substituted C₁-C₆₀alkyl group, the substituted C₂-C₆₀ alkenyl group, the substitutedC₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, thesubstituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, thesubstituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ arylgroup, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substitutedmonovalent non-aromatic condensed polycyclic group, and the substitutedmonovalent non-aromatic condensed heteropolycyclic group is selectedfrom: deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,—CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group,a hydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, aC₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group,each substituted with at least one selected from deuterium, —F, —Cl,—Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉); aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂,—CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, anamidino group, a hydrazine group, a hydrazone group, a carboxylic acidgroup or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂),—Si(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉); and—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉),and Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ are eachindependently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkyl groupsubstituted with at least one selected from deuterium, a C₁-C₆₀ alkylgroup, and a C₆-C₆₀ aryl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl groupsubstituted with at least one selected from deuterium, a C₁-C₆₀ alkylgroup, and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromaticcondensed polycyclic group, and a monovalent non-aromatic condensedheteropolycyclic group.
 2. The organometallic compound of claim 1,wherein a bond between A₁ and M and a bond between X₄ and M are each acoordinate bond, and a bond between X₂ and M and a bond between X₃ and Mare each a covalent bond.
 3. The organometallic compound of claim 1,wherein rings CY₁ to CY₄ are each independently selected from a benzenegroup, a naphthalene group, an anthracene group, a phenanthrene group, atriphenylene group, a pyrene group, a chrysene group, a cyclopentadienegroup, a 1,2,3,4-tetrahydronaphthalene group, a furan group, a thiophenegroup, a silole group, an indene group, a fluorene group, an indolegroup, a carbazole group, a benzofuran group, a dibenzofuran group, abenzothiophene group, a dibenzothiophene group, a benzosilole group, adibenzosilole group, an azafluorene group, an azacarbazole group, anazadibenzofuran group, an azadibenzothiophene group, an azadibenzosilolegroup, a pyridine group, a pyrimidine group, a pyrazine group, apyridazine group, a triazine group, a quinoline group, an isoquinolinegroup, a quinoxaline group, a quinazoline group, a phenanthroline group,a pyrrole group, a pyrazole group, an imidazole group, a triazole group,an oxazole group, an isoxazole group, a thiazole group, an isothiazolegroup, an oxadiazole group, a thiadiazole group, a benzopyrazole group,a benzimidazole group, a benzoxazole group, a benzothiazole group, abenzooxadiazole group, a benzothiadiazole group, a5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinolinegroup.
 4. The organometallic compound of claim 1, wherein at least oneof rings CY₂ and CY₄ is a condensed ring with at least one 5-memberedring and at least one 6-membered ring, the 5-membered ring is selectedfrom a cyclopentadiene group, a furan group, a thiophene group, apyrrole group, a silole group, an oxazole group, an isoxazole group, anoxadiazole group, an isoxadiazole group, an oxatriazole group, anisoxatriazole group, a thiazole group, an isothiazole group, athiadiazole group, an isothiadiazole group, a thiatriazole group, anisothiatriazole group, a pyrazole group, an imidazole group, a triazolegroup, a tetrazole group, an azasilole group, a diazasilole group, and atriazasilole group, and the 6-membered ring is selected from acyclohexane group, a cyclohexene group, a benzene group, a pyridinegroup, a pyrimidine group, a pyrazine group, and a pyridazine group. 5.The organometallic compound of claim 1, wherein T₂ is a single bond. 6.The organometallic compound of claim 1, wherein R₁ to R₆, R₃₁, and R₃₂are each independently selected from: hydrogen, deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxylic acidgroup or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, —SF₅, a C₁-C₂₀ alkyl group, anda C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group,each substituted with at least one selected from deuterium, —F, —Cl,—Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₁₀ alkyl group, a cyclopentyl group, acyclohexyl group, a cycloheptyl group, a cyclooctyl group, anadamantanyl group, a norbornanyl group, a norbornenyl group, acyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, aphenyl group, a naphthyl group, a pyridinyl group, and a pyrimidinylgroup; a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclooctyl group, an adamantanyl group, a norbornanyl group, anorbornenyl group, a cyclopentenyl group, a cyclohexenyl group, acycloheptenyl group, a phenyl group, a naphthyl group, a fluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group,an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a dibenzosilolyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a cyclooctyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group, a cyclopentenyl group, acyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group,a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group, each substituted with at leastone selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃,—CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkylgroup, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a cyclooctyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group, a cyclopentenyl group, acyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthylgroup, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a pyrrolyl group, a thiophenyl group, a furanyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolylgroup, an indolyl group, an indazolyl group, a purinyl group, aquinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group,a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, an imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅); and—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉), wherein Q₁to Q₉ and Q₃₃ to Q₃₅ may each independently be selected from: —CH₃,—CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃,—CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and —CD₂CDH₂; ann-propyl group, an iso-propyl group, an n-butyl group, an iso-butylgroup, a sec-butyl group, a tert-butyl group, an n-pentyl group, anisopentyl group, a sec-pentyl group, a tert-pentyl group, a phenylgroup, and a naphthyl group; and an n-propyl group, an iso-propyl group,an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butylgroup, an n-pentyl group, an isopentyl group, a sec-pentyl group, atert-pentyl group, a phenyl group, and a naphthyl group, eachsubstituted with at least one selected from deuterium, a C₁-C₁₀ alkylgroup, and a phenyl group.
 7. The organometallic compound of claim 1,wherein R₁ to R₆, R₃₁, and R₃₂ may each independently be selected fromhydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, —CH₃, —CD₃,—CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, groups represented by Formulae 9-1 to9-19, groups represented by Formulae 10-1 to 10-161, —N(Q₁)(Q₂),—Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉):

wherein, in Formulae 9-1 to 9-19 and 10-1 to 10-161, “Ph” indicates aphenyl group, “TMS” indicates a trimethylsilyl group, and * indicates abinding site to a neighboring atom.
 8. An organometallic compoundrepresented by Formula 1:

wherein, in Formula 1, M is beryllium (Be), magnesium (Mg), aluminum(Al), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper(Cu), zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium(Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum(Pt), or gold (Au), two bonds selected from a bond between A₁ and M, abond between X₂ and M, a bond between X₃ and M, and a bond between X₄and M are each a covalent bond, and the others thereof are each acoordinate bond, A₁ is a first atom linked to M, a non-cyclic moietycomprising the first atom linked to M, or ring CY₁ comprising X₁ linkedto M and substituted with groups R₁ in the number of a₁, the first atomis B, N, P, C, Si, O, or S, rings CY₁ to CY₄ are each independentlyselected from a C₅-C₃₀ carbocyclic group and a C₁-C₃₀ heterocyclicgroup, a cyclometalated ring formed by A₁, CY₂, and M is a 5-memberedring, X₁ to X₄ are each independently N or C, X₃₁ is C(R₃₁) or N, andX₃₂ is C(R₃₂), wherein, when X₃₁ is C(R₃₁), R₃₁ and R₃₂ are not linkedto each other, T₁ and T₂ may each independently be selected from asingle bond, a double bond, *—N(R₅)—*′, *—B(R₅)—*′, *—P(R₅)—*′,*—C(R₅)(R₆)—*′, *—Si(R₅)(R₆)—*′, *—Ge(R₅)(R₆)—*′, *—S—*′, *—Se—*′,*—O—*′, *—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₅)═*′, *═C(R₅)—*′,C(R₅)═C(R₆)—*′, *—C(═S)—*′, and *—C≡C—*′, and * and *′ each indicate abinding site to a neighboring atom, R₅ and R₆ are optionally linked viaa single bond, a double bond, or a first linking group to form asubstituted or unsubstituted C₅-C₃₀ carbocyclic group or a substitutedor unsubstituted C₁-C₃₀ heterocyclic group, R₁ to R₆, R₃₁, and R₃₂ areeach independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I,—SF₅, a hydroxyl group, a cyano group, a nitro group, an amidino group,a hydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkylgroup, a substituted or unsubstituted C₂-C₆₀ alkenyl group, asubstituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅),—B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉), a₁ to a₄ are each independently aninteger from 0 to 20, two of a plurality of neighboring groups R₁ areoptionally linked to form a substituted or unsubstituted C₅-C₃₀carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclicgroup, two of a plurality of neighboring groups R₂ are optionally linkedto form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group, two of aplurality of neighboring groups R₃ are optionally linked to form asubstituted or unsubstituted C₅-C₃₀ carbocyclic group or a substitutedor unsubstituted C₁-C₃₀ heterocyclic group, two of a plurality ofneighboring groups R₄ are optionally linked to form a substituted orunsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstitutedC₁-C₃₀ heterocyclic group, two or more neighboring groups selected fromR₁ to R₄ are optionally linked to form a substituted or unsubstitutedC₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀heterocyclic group, at least one substituent of the substituted C₅-C₃₀carbocyclic group, the substituted C₁-C₃₀ heterocyclic group, thesubstituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group,the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxygroup, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, thesubstituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ arylgroup, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substitutedmonovalent non-aromatic condensed polycyclic group, and the substitutedmonovalent non-aromatic condensed heteropolycyclic group is selectedfrom: deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,—CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group,a hydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, aC₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group,each substituted with at least one selected from deuterium, —F, —Cl,—Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉); aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, and a monovalentnon-aromatic condensed heteropolycyclic group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂,—CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, anamidino group, a hydrazine group, a hydrazone group, a carboxylic acidgroup or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂),—Si(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉); and—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉),and Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ are eachindependently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkyl groupsubstituted with at least one selected from deuterium, a C₁-C₆₀ alkylgroup, and a C₆-C₆₀ aryl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl groupsubstituted with at least one selected from deuterium, a C₁-C₆₀ alkylgroup, and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromaticcondensed polycyclic group, and a monovalent non-aromatic condensedheteropolycyclic group.
 9. The organometallic compound of claim 1,wherein A₁ is selected from moieties represented by Formulae CY1-1 toCY1-44 and A1-1 to A1-4:

wherein, in Formulae CY1-1 to CY1-44 and A1-1 to A1-4, X₁ and R₁ are thesame as described in claim 1, X₁₁ is O, S, C(R₁₁)(R₁₂), or Si(R₁₁)(R₁₂),R₁₁ to R₁₈ are the same as described in connection with R₁ in claim 1,a16 is an integer from 0 to 6, a15 is an integer from 0 to 5, a14 is aninteger from 0 to 4, a13 is an integer from 0 to 3, a12 is an integerfrom 0 to 2, * indicates a binding site to M in Formula 1, and *′indicates a binding site to ring CY₂ in Formula
 1. 10. Theorganometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is represented by one of Formulae CY2-1 to CY2-45:

wherein, in Formulae CY2-1 to CY2-45, X₂ and R₂ are the same asdescribed in claim 1, X₂₁ is O, S, N(R₂₁), C(R₂₁)(R₂₂), or Si(R₂₁)(R₂₂),R₂₁ to R₂₈ are the same as described in connection with R₂ in claim 1,a26 is an integer from 0 to 6, a25 is an integer from 0 to 5, a24 is aninteger from 0 to 4, a23 is an integer from 0 to 3, a22 is an integerfrom 0 to 2, * indicates a binding site to M in Formula 1, *′ indicatesa binding site to A₁ in Formula 1, and *″ indicates a binding site to T₁in Formula
 1. 11. The organometallic compound of claim 1, wherein amoiety represented by

in Formula 1 is represented by one of Formulae CY3-1 to CY3-10:

wherein, in Formulae CY3-1 to CY3-10, X₃, R₃, X₃₁, and X₃₂ are the sameas described in claim 1, R₃₁ to R₃₈ are the same as described inconnection with R₃ in claim 1, a34 is an integer from 0 to 4, a33 is aninteger from 0 to 3, a32 is an integer from 0 to 2, * indicates abinding site to M in Formula 1, *″ indicates a binding site to T₁ inFormula 1, and *′ indicates a binding site to T₂ in Formula
 1. 12. Theorganometallic compound of claim 1, wherein a moiety represented in

in Formula 1 is represented by one of Formulae CY4-1 to CY4-44:

wherein, in Formulae CY4-1 to CY4-44, X₄ and R₄ are the same asdescribed in claim 1, X₄₁ is O, S, N(R₄₁), C(R₄₁)(R₄₂), or Si(R₄₁)(R₄₂),R₄₁ to R₄₈ are the same as described in connection with R₄ in claim 1,a₄₆ is an integer from 0 to 6, a₄₅ is an integer from 0 to 5, a₄₄ is aninteger from 0 to 4, a₄₃ is an integer from 0 to 3, a₄₂ is an integerfrom 0 to 2, * indicates a binding site to M in Formula 1, and *′indicates a binding site to T₂ in Formula
 1. 13. The organometalliccompound of claim 1, wherein A₁ is selected from moieties represented byFormulae CY1(1) to CY1(19), a moiety represented by

is represented by one of Formulae CY2(1) to CY2(13), a moietyrepresented by

is represented by one of Formulae CY3(1) to CY3(18), and a moietyrepresented by

is represented by one of Formulae CY4(1) to CY4(11):

wherein, in Formulae CY1(1) to CY1(19), CY2(1) to CY2(13), CY3(1) toCY3(18), and CY4(1) to CY4(11), X₁ to X₄, R₁ to R₄, R₃₁, and R₃₂ are thesame as described in claim 1, X₁₁ is O, S, N(R₁₁), C(R₁₁)(R₁₂), orSi(R₁₁)(R₁₂), X₂₁ is O, S, N(R₂₁), C(R₂₁)(R₂₂), or Si(R₂₁)(R₂₂), X₄₁ isO, S, N(R₄₁), C(R₄₁)(R₄₂), or Si(R₄₁)(R₄₂), R_(1a) to R_(1d), R₁₁, andR₁₂ are the same as described in connection with R₁ in claim 1, R_(2a),R_(2b), R₂₁, and R₂₂ are the same as described in connection with R₂ inclaim 1, R_(4a) to R_(4d), R₄₁, and R₄₂ are the same as described inconnection with R₄ in claim 1, * in Formulae CY1(1) to CY1(19), CY2(1)to CY2(13), CY3(1) to CY3(18), and CY4(1) to CY4(11) indicates a bindingsite to M in Formula 1, *′ in Formulae CY1(1) to CY1(19) indicates abinding site to ring CY2 in Formula 1, *′ in Formulae CY2(1) to CY2(13)indicates a binding site to A₁ in Formula 1, *″ in Formulae CY2(1) toCY2(13) indicates a binding site to T₁ in Formula 1, *″ in FormulaeCY3(1) to CY3(18) indicates a binding site to T₁ in Formula 1, *′ inFormulae CY3(1) to CY3(18) indicates a binding site to T₂ in Formula 1,and *′ in Formulae CY4(1) to CY4(11) indicates a binding site to T₂ inFormula
 1. 14. The organometallic compound of claim 1, wherein theorganometallic compound is represented by Formula 1-1:

wherein, in Formula 1-1, M, A₁, X₂ to X₄, CY₂ to CY₄, X₃₁, X₃₂, T₂, R₂to R₄, and a₂ to a₄ are the same as described in claim 1, X₉ and X₁₀ areeach independently C or N, CY₉ and CY₁₀ are each independently selectedfrom a C₅-C₃₀ carbocyclic group and a C₁-C₃₀ heterocyclic group, R₉ andR₁₀ are the same as described in connection with R₁ in claim 1, a₉ anda₁₀ are the same as described in connection with a1 in claim 1, T₃ is C,Si, or Ge, T₄ may be selected from a single bond, a double bond,*—N(R₇)—*′, *—B(R₇)—*′, *—P(R₇)—*′, *—C(R₇)(R₈)—*′, *—Si(R₇)(R₈)—*′,*—Ge(R₇)(R₈)—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′,*—S(═O)₂—*′, *—C(R₇)═*′, *═C(R₇)—*′, *—C(R₇)═C(R₈)—*′, *—C(═S)—*′, and*—C≡C—*′, R₇ and R₈ are the same as described in connection with R₅ inclaim 1, and * and *¹ each indicate a binding site to a neighboringatom.
 15. The organometallic compound of claim 1, wherein theorganometallic compound is one of Compounds 1 to 105 below:


16. An organic light-emitting device comprising: a first electrode; asecond electrode; and an organic layer disposed between the firstelectrode and the second electrode, wherein the organic layer comprisesan emission layer and at least one of the organometallic compound ofclaim
 1. 17. The organic light-emitting device of claim 16, wherein thefirst electrode is an anode, the second electrode is a cathode, theorganic layer further comprises a hole transport region disposed betweenthe first electrode and the emission layer and an electron transportregion disposed between the emission layer and the second electrode,wherein the hole transport region comprises a hole injection layer, ahole transport layer, an electron blocking layer, or any combinationthereof, and wherein the electron transport region comprises a holeblocking layer, an electron transport layer, an electron injectionlayer, or any combination thereof.
 18. The organic light-emitting deviceof claim 16, wherein the emission layer comprises the organometalliccompound.
 19. The organic light-emitting device of claim 18, wherein theemission layer further comprises a host, and an amount of the host islarger than an amount of the organometallic compound.
 20. A diagnosticcomposition comprising at least one of the organometallic compound ofclaim 1.